
package kaizone.haining.chaobohui.widget;

import android.content.Context;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.util.FloatMath;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;

public class ZoomImageView extends ImageView implements OnTouchListener {

    private static final String TAG = "ZoomImageView";

    // These matrices will be used to move and zoom image
    Matrix matrix = new Matrix();

    Matrix savedMatrix = new Matrix();

    // We can be in one of these 3 states
    static final int NONE = 0;

    static final int DRAG = 1;

    static final int ZOOM = 2;

    int mode = NONE;

    // Remember some things for zooming
    PointF start = new PointF();

    PointF mid = new PointF();

    float oldDist = 1f;

    protected Context mContext;

    public ZoomImageView(Context context) {
        this(context, null);
    }

    public ZoomImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mContext = context;
        setScaleType(ScaleType.FIT_XY);
        setOnTouchListener(this);
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        ImageView view = (ImageView) v;
        view.setScaleType(ScaleType.MATRIX);
        // Dump touch event to log
        dumpEvent(event);
        // Handle touch events here...
        switch (event.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN:
                savedMatrix.set(matrix);
                start.set(event.getX(), event.getY());
                Log.d(TAG, "mode=DRAG");
                mode = DRAG;
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                oldDist = spacing(event);
                Log.d(TAG, "oldDist=" + oldDist);
                if (oldDist > 10f) {
                    savedMatrix.set(matrix);
                    midPoint(mid, event);
                    mode = ZOOM;
                    Log.d(TAG, "mode=ZOOM");
                }
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_POINTER_UP:
                mode = NONE;
                Log.d(TAG, "mode=NONE");
                break;
            case MotionEvent.ACTION_MOVE:
                if (mode == DRAG) {
                    // ...
                    matrix.set(savedMatrix);
//                    matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);
                } else if (mode == ZOOM) {
                    float newDist = spacing(event);
                    Log.d(TAG, "newDist=" + newDist);
                    if (newDist > 10f) {
                        matrix.set(savedMatrix);
                        float scale = newDist / oldDist;
//                        matrix.postScale(scale, scale, mid.x, mid.y);
                        if(scale > 0.5f && scale <2.0f){
                        	matrix.postScale(scale, scale, getWidth()/2, getHeight()/2);
                        }
                    }
                }
                break;
        }
        view.setImageMatrix(matrix);
        return true; // indicate event was handled
    }

    /** Show an event in the LogCat view, for debugging */
    private void dumpEvent(MotionEvent event) {
        String names[] = {
                "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE", "POINTER_DOWN", "POINTER_UP", "7?",
                "8?", "9?"
        };
        StringBuilder sb = new StringBuilder();
        int action = event.getAction();
        int actionCode = action & MotionEvent.ACTION_MASK;
        sb.append("event ACTION_").append(names[actionCode]);
        if (actionCode == MotionEvent.ACTION_POINTER_DOWN
                || actionCode == MotionEvent.ACTION_POINTER_UP) {
            sb.append("(pid ").append(action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
            sb.append(")");
        }
        sb.append("[");
        for (int i = 0; i < event.getPointerCount(); i++) {
            sb.append("#").append(i);
            sb.append("(pid ").append(event.getPointerId(i));
            sb.append(")=").append((int) event.getX(i));
            sb.append(",").append((int) event.getY(i));
            if (i + 1 < event.getPointerCount())
                sb.append(";");
        }
        sb.append("]");
        Log.d(TAG, sb.toString());
    }

    /** Determine the space between the first two fingers */
    private float spacing(MotionEvent event) {
        float x = event.getX(0) - event.getX(1);
        float y = event.getY(0) - event.getY(1);
        return FloatMath.sqrt(x * x + y * y);
    }

    /** Calculate the mid point of the first two fingers */
    private void midPoint(PointF point, MotionEvent event) {
        float x = event.getX(0) + event.getX(1);
        float y = event.getY(0) + event.getY(1);
        point.set(x / 2, y / 2);
    }
}
